Known apparatus for heating using rotating magnets and material acted on by them for heat producing purposes include the following U.S. patents:
No. 2,912,552 to M. Baerman shows embodiments in which magnet arrays are passed by laminated pole pieces edge-on to the magnets, and also are passed by laminates of metal sheets perpendicular to the metal sheets;
No. 3,272,956 to M. Baerman, 9-13-66, shows apparatus for heating elongate material with magnets; and
No. 4,217,475 to J. P. Hagerty, 8-12-80, shows fluid heating magnet apparatus with sleeves.